LED’s- No UV? Do corals need UV for longterm health?

[jda]

Probably a worthwhile exercise if ever made. There is enough market share that companies are making new MH bulbs with dual arc and new color mixes with less IR and stuff. Giesemann, Hamilton and ReefBrite all make enough money to R&D and sell new MH bulbs in the last few years.

 

[J1a]

@Dana Riddle you talked about photo inhibition under over-illuminated conditions. Would these conditions lead to more production of florescent proteins as a coping mechanism? If so, that will be fairly desirable.

A second question which bugs me for a long time: What is the best way to reconcile the lighting needs of acroporas and clams? Clams in general accepts very high Par before photos inhibition even sets in, yet they are often placed near the sand bed due to size etc. Is there a better way to cope with this?

 

[jda]

Clams can digest excess zoox and can get energy from them. There is nearly no way to over illuminate them as long as you don't shock them. Corals don't have this complex of a system. They are quite different.

For me, acropora lighting seem to depend on quality. The higher the quality, the more quantity they are happy to get. The acros in the photo below get 2000+ PAR and grow like crazy, but they have the best light. Acros in a shallow tub under the sun one summer in Missouri less than a foot deep grew like crazy and looked great once I got them back inside - sun is awesome. I can drop 1500 PAR from a good reef quality MH bulb on acropora and they react with faster growth* - this is not necessary, but it can happen. T5 seems to max out at 800-900, or so. While some can get LEDS over 400, most cannot without harming them.

To me, this all ties back in to the discussion at hand, which is missing wavelengths... Assume that all of the corals mostly are suite to live under the sun, so it is pure, for this assumption. MH is next with the widest range of output and wavelengths. T5 is next. LED last. Nobody knows why or how or what is important on a wholistic level, so this is somewhat anecdotal, but does anybody else have a better explanation at this level? We can argue over what part of the quality is missing, but it has to be something, right?

My supposition is the very high energy UV and then also IR to allow energy to move between the photosystems. 350 to 850nm is super important... all of it.

Nobody can argue that coral need all of this, but humans can live for probably 60 years on a diet of only McDonalds and need nothing else. We just don't know in totality, but the signs point to higher quality delivering more positive results.

*I have seen some general purpose or ag bulbs struggle at super high PAR with acropora... not reef bulbs or bulbs that have proven over the decades to be good reef bulbs. This was mostly back before 10k and 14k bulbs were available and 5500k, 6500k, etc. bulbs were used. Needed to keep some of these under 1000, or so, PAR or they did not do much else. These can be great bulbs and I have used them, mostly to land wild colonies from a trans ship, but I keep them 750, or so PAR.

 

[J1a]

@jda I assume but quality you are referring to the spectral range and proportion? I would certainly agree with you.

 

[outhouse]

Clams can digest excess zoox and can get energy from them. There is nearly no way to over illuminate them as long as you don't shock them. Corals don't have this complex of a system. They are quite different.

For me, acropora lighting seem to depend on quality. The higher the quality, the more quantity they are happy to get. The acros in the photo below get 2000+ PAR and grow like crazy, but they have the best light. Acros in a shallow tub under the sun one summer in Missouri less than a foot deep grew like crazy and looked great once I got them back inside - sun is awesome. I can drop 1500 PAR from a good reef quality MH bulb on acropora and they react with faster growth* - this is not necessary, but it can happen. T5 seems to max out at 800-900, or so. While some can get LEDS over 400, most cannot without harming them.

To me, this all ties back in to the discussion at hand, which is missing wavelengths... Assume that all of the corals mostly are suite to live under the sun, so it is pure, for this assumption. MH is next with the widest range of output and wavelengths. T5 is next. LED last. Nobody knows why or how or what is important on a wholistic level, so this is somewhat anecdotal, but does anybody else have a better explanation at this level? We can argue over what part of the quality is missing, but it has to be something, right?

My supposition is the very high energy UV and then also IR to allow energy to move between the photosystems. 350 to 850nm is super important... all of it.

Nobody can argue that coral need all of this, but humans can live for probably 60 years on a diet of only McDonalds and need nothing else. We just don't know in totality, but the signs point to higher quality delivering more positive results.

*I have seen some general purpose or ag bulbs struggle at super high PAR with acropora... not reef bulbs or bulbs that have proven over the decades to be good reef bulbs. This was mostly back before 10k and 14k bulbs were available and 5500k, 6500k, etc. bulbs were used. Needed to keep some of these under 1000, or so, PAR or they did not do much else. These can be great bulbs and I have used them, mostly to land wild colonies from a trans ship, but I keep them 750, or so PAR.

Makes sense. My view of adding led UV bars to my led lights was to try and mimic MH as close as one can. I filled a 220g tank in 2 years with LPS that started at 20% filled. Leds can't match that, so I'm on a quest to see if I can get close as I can

 

[GoVols]

I know that you did not ask me, but making LED act and look like MH would take away most of their real, and perceived, value-add. True UV LEDs are short lived, ruin lenses and need replaced probably faster than MH bulbs do - you could make sockets and replace them, but then the value-add about not replacing bulbs is gone. Glass lenses could be used on UV LEDs, but another expense and the LEDS themselves would still need replaced. Using IR would add heat. Many would soon realize that this is mostly a bogus argument since most heat is easily managed if you want to, but the talking point is gone. Both would use more power in a realm where there is not really much power savings anyway as long as you are not choosing way too much of one kind or another. In the end, the people who want all of this stuff probably just would use a Halide anyway, so is there enough of a market share to mess with it? Most people who go to an online site or LFS and buy a LED don't know lighting from shineola.

I don't know that anybody has figured out how to beat the reflector with an LED. I mostly have larger tanks, so my experience is with those and I admittedly have little experience or interst in smaller, shallower tanks or nanos, but you need at least 250w of LED to replace a 250w Halide for my acropora and clams, so if you had to reflect that LED the spread would be a tremendous improvement, but the efficiency would go down. They are already pretty much equal on wattage in the real world on tanks like mine. I have not yet seen any good answers for a reflector. The best that I have seen is wide panels way up high where the light blends better, but there is still shadowing beyond what reflectors have - like a Photon V2 the way that therman uses them, for example.

Thanks jda

I was hoping that you would chime in

 

[Reefahholic]

There’s definitely something about metal halides that grows corals very well. I would honestly love to know if it is the UV since they seem to have a lot of it.

 

[outhouse]

There’s definitely something about metal halides that grows corals very well. I would honestly love to know if it is the UV since they seem to have a lot of it.

Im wondering if one may need to use much more UV leds in light of leds lack of true and near UV depending on brands.

Dana says coral do not need it, and he is probably right, but will led UV or near UV grow coral? sure it will he said it would as well. Maybe were not asking the right question with the OP.

Those companies that do provide it in their spectrums seem to be using some but maybe its not enough to equal MH growth.

 

[J1a]

I have temporarily rigged a 12w UV light strip over my aquarium. it's 1:1 ratio of 365nm and 380nm diodes

Seems like it does give a small bump in the UV region, but surely not very significant.

Let's see what this will do/if this will do anything.

 

[Reefahholic]

What can’t LED manufacturers make LED’s that duplicate the Metal Halide spectrum and have a good amount of UV.

Why is this hard to do?

 

[J1a]

I

What can’t LED manufacturers make LED’s that duplicate the Metal Halide spectrum and have a good amount of UV.

Why is this hard to do?

I think one of the biggest issue is that the leds have narrow band of wavelength in nature. Probably need a lot more LED to cover the whole spectrum, to get the same Par. Since the UV and IR ranges are not part of Par measurement, manufacturers probably don't have much incentive to include those.

Another issue with LED is the illusion of control. With so many channels, a lot of parameters could be in jeopardy.

 

[jda]

Not needing something, and doing better with it are two different things... like my McDonalds diet example above... no person NEEDS more than they offer at fast food, but don't we all know to do better than this?

I laid out above why LED companies don't try and mimic MH anymore (they tried at first)... diode changes, more wattage and heat. It takes away their value add, although most of it is perceived, but it still does. You can talk to some of them if we ever have a MACNA in person again... the smart ones (not the sales people) will flat out tell you... they manufacture for the leading edge and ones who respond to the talking points. The ones that do not don't use their stuff anyway since they know that there is no energy savings, heat is no problem and bulb changes are not as expensive as new panels right now if you don't expect them to last forever like so many do.

I keep mentioning this, but don't forget about IR. IR helps move energy between the photosystems. More energy means more growth, healthier coral and all of that.

 

[outhouse]

What can’t LED manufacturers make LED’s that duplicate the Metal Halide spectrum and have a good amount of UV.

Why is this hard to do?

Lots of possibilities. How much does shimmer work or not work. Would a 10w led grow better than 3 x 3w. If one had to use more or less of the visible spectrum, is it going to be pleasing to the eye?

Funny I looked at old pics under MH and phone didn't need a filter, and there was a huge amount of bright white light, even with actinic supplements VHO, phone still didn't need a filter.

 

[Hydrored]

I would love to try a metal halide hybrid setup, biggest issue I have with halides is actually the fact they are ugly as hell. Thanks to @sdreef I was looking for a Giesmann Infinity HQI/T5 fixture prior to going all LED again on my 300 and couldn’t find a 72” one anywhere.

If we want halides to make a come back more companies need to make something visually pleasing, that is another area where LED’s have taken more of the market share.

I don’t disagree LED’s have a way to go, I could’ve purchased 4 spectra’s at the same price I paid to cover my tank in LED’s

 

[Reefahholic]

I would love to try a metal halide hybrid setup, biggest issue I have with halides is actually the fact they are ugly as hell. Thanks to @sdreef I was looking for a Giesmann Infinity HQI/T5 fixture prior to going all LED again on my 300 and couldn’t find a 72” one anywhere.

If we want halides to make a come back more companies need to make something visually pleasing, that is another area where LED’s have taken more of the market share.

I don’t disagree LED’s have a way to go, I could’ve purchased 4 spectra’s at the same price I paid to cover my tank in LED’s

You just get two 36” fixtures and butt them together. Easier to sell too.

 

[rtparty]

I would love to try a metal halide hybrid setup, biggest issue I have with halides is actually the fact they are ugly as hell. Thanks to @sdreef I was looking for a Giesmann Infinity HQI/T5 fixture prior to going all LED again on my 300 and couldn’t find a 72” one anywhere.

If we want halides to make a come back more companies need to make something visually pleasing, that is another area where LED’s have taken more of the market share.

I don’t disagree LED’s have a way to go, I could’ve purchased 4 spectra’s at the same price I paid to cover my tank in LED’s

The ReefBrite pendants aren't terrible looking and a simple floating canopy can hide almost all of it.

Giesemann had great looking fixtures but at the cost of terrible reflectors with intense hotspots.

 

[ZoWhat]

What can’t LED manufacturers make LED’s that duplicate the Metal Halide spectrum and have a good amount of UV.

Why is this hard to do?

IMO/IME 380-400nm violet lights run super hot. Exxxxxxxtremely hot.

Those diodes pumping out violet sub400nm are usually the first diodes to 'pop' and burn up due to heat.

Very difficult to keep those diodes cool thru a decent warranty period. Life of sub400nm diodes are usually 6-9mos at the rate we run them. Longer life requires extreme measures in cooling design. (oversized aluminum fins and loud air flow)

Second issue us you need a LOT of wattage to penetrate sub400nm. Like double/triple the wattage of every other diode

Mfgrs don't want to out any warranty on lights that run that hot IMO..... so they usually stop at 410/420nm.


.

 

[J1a]

IMO 380-400nm violet lights run super hot. Exxxxxxxtremely hot.

Those diodes pumping out violet sub400nm are usually the first diodes to 'pop' and burn up due to heat.

Very difficult to keep those diodes cool.

Second issue us you need a LOT if wattage to penetrate sub400nm. Like double wattage of every other diode

Mfgrs don't want to out any warranty on lights that run that hot IMO..... so they stop at 420nm.


.

So the most logical solution is dedicated supplementary light engineered for proper cooling and UV intensity.

Perhaps can throw in some IR as well while we are at it.

 

[damsels are not mean]

For me, acropora lighting seem to depend on quality. The higher the quality, the more quantity they are happy to get. The acros in the photo below get 2000+ PAR and grow like crazy, but they have the best light. Acros in a shallow tub under the sun one summer in Missouri less than a foot deep grew like crazy and looked great once I got them back inside - sun is awesome. I can drop 1500 PAR from a good reef quality MH bulb on acropora and they react with faster growth* - this is not necessary, but it can happen. T5 seems to max out at 800-900, or so. While some can get LEDS over 400, most cannot without harming them.

2000 PAR? Maybe but not all day. The average would be much lower. I remember a slide from Dana's macna talk about the peak photosynthetic range of PAR being in the 100-200 range for most corals.

What is "quality" here? Daylight at a high par value is going to be less concentrated in the important photosynthetic regions as far as spectrum than most light fixtures. Are corals growing fast under 2000 PAR of sunlight because it's "quality light" or because not as much of that spectrum is actually being utilized by the coral/symbiodinium (this is the concept of PUR)? We know that photosynthesis in these organisms peaks at certain wavelengths. If you nail the coral with 2000 PAR of royal blue LED for 12 hours a day it's a whole lot brighter as far as the coral is concerned than a daily peak of 2000 or maybe even 1000 or 500 of sunlight.

 

[outhouse]

Life of sub400nm diodes are usually 6-9mos at the rate we run them.

Not any more, they figured away around all that. no fans, just huge heatsink, and the main trick, is under driving them by almost 2/3 so by giving them 1/3 the power at 100% intensity, they can get years out of them. Orphik and reefbreeders are doing exactly that.